Diesel fuel injector pump



. June 16, 1942, w. L. PIPKIN, JR

DIESEL FUEL INJECTOR PUMP Filed May 12, 1939 Patented June 16, 1942UNITED STATES PATENT oFFIce DIESEL'FUEL mmc'roa PUMP William LouisPipkin, In, Chicago, 1n. 7

Application May 12, 1939, Serial No. 273,258

4- Claims.

This invention relates to Diesel engines and particularly to the pumpingand distributing of the fuel under pressure to the individual cylinders.

The principal object of this invention is to provide a pumping anddistributing unit having a reciprocating and rotatable plunger that isadjustable as to its stroke so as to regulate the quantity of fueldelivered.

Other objects of this invention relate to the provision of a simple,economical, emcient and compact arrangement for rotating andreciprocating the plunger, to facilitate assembly of the parts and toobtain other advantages hereinafter appearing.

With the foregoing in view the invention re sides in the novelarrangement and combination of parts and in the details of constructionhereinafter described and claimed, it being understood that changes inthe precise embodiment of the invention herein disclosed may be madewithin the scope of what is claimed without departing from the spirit ofthe invention.

A practical embodiment of the invention is illustrated in theaccompanying drawing, wherein:

Figure 1 is a vertical sectional view of the fuel ill being ofsubstantially cylindrical form as at l2 to form a pump chamber and thechamber ll being formed along its lower edge with a flange i3 carryingthe bolts 84 for attaching the housing iii to a suitable support IS onthe Diesel engine (not shown). The cylindrical portion l2 of the housingl0, constitutes the pump chamber and is provided with an axial bore llterminating at its upper end in an enlarged diameter threaded openingl8. Positioned within said opening I 8 is the threaded end IQ of aflanged nipple 20, there being provided between the flange 2| of thenipple and upper end of the pump chamber l2, a packing 22 so as toprovide a liquid tight connection.

The nipple 2B is adapted to have connected thereto a conduit (not shown)for connecting the pump chamber l2 to a source of fuel supply (notshown), and is formed with an axial passage 23 terminating at its lowerend in a valve seat 24 the ball valve 25 seated, said spring at itslower end being positioned on an annular shoulder 21 formed in the borell.

At the lower end of the pump chamber l2 there is provided a cylindricalopening co-axial with the bore ii and in open communication with thebottom chamber ii. Suitably supported within the opening 30 forrotational movement therein is the hub SI of a bevel gear 32, therebeing provided between the gear 32 and base of the pump chamber ananti-friction bearing 33. Mounted in one wall 34 of the bottom chamberIi through the medium of the antifriction bearing 35 is a bevel gear 36adapted to mesh with the bevel gear 32. Rotation of said gears iseffected by a shaft 37 extending axially through-the gear 36 andtransversely across the bottom chamber ii, the end of the shaft 31 beingmounted in the anti-friction bearing 38 'supported in the wall 39opposite the wall 34,.the gear 36 being secured to the shaft 31: forrotation therewith, in any desired manner. The shaft 37 is disposed asto extend diametrically beneath the opening 35 and has fixedly mountedthereon a cam 40 so positioned as to lie in a plane co-incident with theaxis of the opening 30.

Mounted for reciprocating movement within the bore i1 is a plunger 42provided at its lower end with a splined head 43 arranged forreciprocatory and guiding movement in the splined bore 44 of the gearboss 3!. Surrounding the plunger 42 within the opening 30 is a coilspring 45 engaging at its ends the inner face of the splined head 43 andthe base of the opening 30, said spring acting to urge the plunger 42 ina downwardly direction and to maintain the splined head 43 in engagementwith the cam 40.

The plunger-42 is provided with an axial passage 46 communicating withupper and lower transverse ports 41 and 48, the lower port opening intoan annular groove 49 formed in the plunger for a ball valve 25. A coilspring 26 acts to retain 42, for a purpose to be hereinafter described.

Suitably positioned in the wall of the pump chamber l2 are opposedpassages 50 and 5|. Each passage terminates within a threaded boss 52 towhich is detachably secured, respectively, the feed pipes 53 and 54, bymeans of threaded caps 55 in the manner well known. In a like mannerthere is provided below the opposed passages a passage 56 incommunicationwith a return pipe 5'l'similarly connected to the pumpchamber I2 as the'feed pipes 5354. Provided in the wall of the bore ii,are opposed grooves 58 and 59 of a predetermined length and width suchthat in the lowermost position of the plunger 42,

. wedge.

the port 41 will barely be in communication with one or the other ofsaid grooves which communication will be complete for the entire lengthof the stroke of the plunger and for a predetermined part of arevolution thereof as will be hereinafter described. In the form of pumpshown the feed pipes 53 and 54 are each connected to a cylinder of a twocylinder Diesel engine (not shown) and the return pipe 51 is connectedto the fuel supply tank (not shown).

The cycle of operation of the pump is as follows:

The shaft 31 is connected to the engine so asto operate the gears 36 and32, the ratio of which depends on the number of cylinders of the engine.Thus for a two cylinder engine the ratio is 2 to 1," for a four cylinderengine it is "4 to l, and so on, so that in the two cylinder engines theplunger 42 will have two strokes through the action of the cam 40 foreach revolution thereof. In a like manner for a four cylinder engine theplunger 42 will have four strokes for each revolution thereof.

Thus the oil is taken in through nipple 20 under pressure from thesupply pump (not shown) and drawn into the pump bore I! on thedownstroke of the plunger 42. On the upstroke the valve 25 is closed andthe oil is then under pressure being forced into axial passage 46 andout through port 41 into one or the other of grooves 58 or 59, dependingupon the rotary position of the plunger for transmission through thecorresponding passage 50 or and feed pipe 53 or 54 so as to therebydeliver oil to the respective cylinder of the engine,

When the plunger 42 reaches a predetermined position substantially atthe end of its upward stroke the port 48 and groove 49 will registerwith the passage 56 whereupon the delivery of oil through one or theother feed pipes is discontinued allowing the oil to return to thesupply tank through return pipe 51 and at the same time cutting off thepressure to the engine cylinder. By virtue of the annular groove 49there is a return of oil through port 48 intopassage 56 upon thetermination of each upward stroke of the plunger 42.

a rotating plunger that acts as a distributor as well as a high pressurepump.

Having thus described my invention, I claim as new and desire to secureby Letters Patent:

1. In a fuel pump for engines comprising a reciprocatory and rotatableplunger, cam and gear means simultaneously operative to respectivelyreciprocate and rotate said plunger, said cam being arranged beneathsaid plunger and in engagement with the adjacent end thereof, and strokeadjusting means for regulating the amount of fuel pumped comprising awedge adapted to be moved between said cam and plunger end for raisingthe stroke of said plunger, a rod fixed to the base of said wedge, amovable support, said rod being mounted on one end of said support forvertical movement relative thereto, a coil spring surrounding said rodseated between said support and the base of said wedge, manuallyoperated means connected with said support for moving the same includingmeans for locking said support in adjusted position whereby to hold saidwedge in proper position for a selected engine speed.

2. -A fuel pump for a Diesel engine comprising a pump casing, a plungerreciprocal therein, means for reciprocating and rotating said plunger,an axial bore in said plunger, valve means for admitting fuel into thepump chamber on the intake stroke of said plunger, upper and lowertransverse ports connecting said bore with the exterior of said plunger,a plurality of delivery passages in said pump casing arranged in Inorder to control the speed of the engine there is provided a strokeadjusting mechanism, a preferred form see Fig. 2 of which consists of afinely tapered wedge 60 fixed at its base to a rod 6!, said wedge beingadapted to be inserted between the cam 40 and splined plunger head 43.The rod BI is supported for vertical movement on the end of a rack 82,there being provided a coil spring 63 between the base of the wedge andthe rack for resiliently supporting the Movement of the rack 62 isachieved by a pinion 64 carried on the end of a shaft 65 under thecontrol of, a lever 66 which is provided with a conventional form ofspring catch 61, the pinion 64 meshing with the rack. The spring catch6'! acts to hold the lever in adjusted position to thereby retain thewedge 60 in its selected adjusted position. Movement of the wedgeinwardly between the cam 40 and splined plunger head 43 acts to raisethe stroke of the plunger 42 so that the port 48 lines up with thepassage 56 earlier in the stroke thus delivering less oil to thecylinders to thereby provide a reduction in the speed of the engine.

The type of gears may be varied or 'the type of governor (not shown) maybe varied without changing the basic idea which is presented herewith.The principal feature of this invention is radial relation to the axisof said plunger, each of said delivery passages being provided with anindividual conduit formed in said pump casing wall arranged tocommunicate said upper transverse port with an associated deliverypassage for substantially the full length of the pumping stroke of saidplunger at predetermined intervals of rotation of said plunger, a returnpassage in said pump casing, an annular groove formed in said plunger inthe plane of said lower port and providing communication between saidlower port and said return passage at a predetermined point near the endof the pump stroke whereby to relieve the pressure in said pump casingand to interrupt the discharge of fuel therefrom and including a strokeadjusting mechanism operative to raise the pumping stroke of the plungerwhereby said annular groove will register with the return passageearlier in the pump stroke.

3. A fuel pump for a Diesel engine comprising a pump casing, a plungerreciprocal therein, means for reciprocating and rotating said plunger,an axial bore in said plunger, valve means for admitting fuel into thepump chamber on the intake stroke of said plunger, upper and lowertransverse ports connecting said bore with the exterior of said plunger,a plurality of delivery passages in said pump casing arranged in radialrelation to the axis of said plunger, each of said delivery passagesbeing provided with an individual conduit formed in said pump casingwall arranged to communicate said upper transverse port with anassociated delivery passage for substantially the full length of thepumping stroke of said plunger at predetermined intervals of rotation ofsaid plunger, a return passage in said pump casing, an annular grooveformed in said plunger in the plane of said lower port and providingcommunication between said lowerport and said return passage at apredetermined point near the end of the pump stroke whereby to relievethe pressure in said pump casing and to interrupt the discharge of fueltherefrom, wherein said means for reciprocating and rotating saidplunger comprises a driven gear rotatably mounted in said pump casingco-axially with said plunger, a splined sleeve in said gear, a splinedhead on said plunger axially movable on said sleeve, a shaft, a drivegear on said shaft meshing with said driven gear whereby to rotate saidplunger, and a cam on said shaft adapted to engage the end of saidsplined head whereby to reciprocate said plunger, the gear ratio beingsuch that for each revolution of the plunger the cam will impart anumber of pumping strokes to the plunger equal to the number of saiddelivery passages.

4. A fuel pump for a Diesel engine comprising a pump casing, a plungerreciprocal therein,

means for reciprocating and rotating said plunger, an axial bore in saidplunger, valve means for admitting fuel into the pump chamher on theintake stroke of said plunger, upper and lower transverse portsconnecting said bore with the exterior of said plunger, a plurality ofdelivery passages in said pump casing arranged in radial relation to theaxis of said plunger,

each of said delivery passages being provided with an individual conduitformed in said pump casing wall arranged to communicate said uppertransverse port with an associated delivery passage for substantiallythe full length of the pumping stroke of said plunger at predeterminedintervals of rotation of said plunger, a return passage in said pumpcasing, an annular groove formed in said plunger in the plane of saidlower port and providing communication between said lower port and saidreturn passage at a predetermined point near the end of the pump strokewhereby to relieve the pressure in said pump casing and to interrupt thedischarge of fuel therefrom, wherein said means for reciprocating androtating said plunger comprises a driven gear rotatably mounted in saidpump casing coaxial with said plunger, a splined sleeve in said gear, asplined head on said plunger axially movable on said sleeve, a shaft, adrive gear on said shaft meshing with said driven gear whereby to rotatesaid plunger, a cam on said shaft adapted to engage the end of saidsplined head whereby to reciprocate said plunger, a coil springsuracting on said splined pump casing as well as to maintain theengagement of said splined head and cam at all times, the gear ratiobeing such that for each revolution of the-plunger the cam will impart anumber of pumping strokes corresponding to the number of saiddelivery'passages.

WILLIAM LOUIS PIPKIN, JR.

